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Lecture 3

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CHY 423
Mark Cole

01/23/2008 Human Health and the Environment Lecture 3: Waterborne Hazards and Human Health Announcements There have been numerous questions regarding the dates for the midterm and final exam. These dates have yet to be finalized by the registrar’s office. The professor has requested that we have the gym for one room to write in. If this is the case, the midterm examination will take place the week after the reading week. This is just preliminary information as we do not know a day or time. As soon as the date for the midterm is finalized it will be posted on the intranet. The video for lecture one will be posted tomorrow for us to watch. Remember late submissions of assignments will not be accepted period. Assignment 1 Read through the assignment carefully in detail. Ask the TA questions. Give your idea and ask if it is correct. You can ask basically anything you want. After that, if you still do not know what to do, you are not clear, you want to learn more, professor is available from 4PM to 6PM to answer questions regarding the assignment. Go to TA first for the TA is fully responsible for the assignments. The assignment is to be done single-spaced. Question 3 is a maximum of two pages including the references. It could be shorter than two pages. The major idea is important. Find scientific papers published in scientific journals to support your opinion or get more information regarding the question. You can use other books and internet resources to elaborate if you like. Make sure you are getting reliable information from the web. Try to be original and do not be repetitive. Question 1: Discuss environmental risks to your health. Explain: this is the risk; I have that risk that will affect my health, what will happen to me, are you going to potentially experience some lung damage or is it cancerous – say why and how you know that. Did you learn that in lecture, read it in a book, is it from the internet, how do you know that risk is associated with that health affect. Make sure that you explain. What type of risks or hazards? The hazards include chemical, physical, social, biological, cultural or environmental hazards. Is this a season of flu? Do you take TTC, drink tap water, smoke, drink, and/or drive a car (indoor environment) – many different risks. Do you eat breakfast, does your roommate smoke. Can we have an overlapping of the risks? It could be but try not to do it because if you have idea for five you do not have to repeat it. Question 2: An explanation is needed. If you start right away you can get help from TA. Liquid natural capitol • Water generally is a liquid capitol, natural capitol • Why is it natural? Water is available everywhere in nature, we are surrounded by water • Even our body is mostly consisted of water • Earth is a water planet – 71% of our surface is covered with water • Not all of this water is available for us for our consumption • Why? Mostly salty water – we are surrounded by huge oceans and huge seas Life Support EESA10H3 S 01/23/2008 • Not much fresh water that we can use for human consumption and animal consumption • Why is water so important? No living species (animals, plants, or humans) can survive and live without water • We always think about drinking though water is not just for drinking • Everything in household from cleaning to cooking, industrial purposes, agriculture (for watering plants and crops) • There is a science called geomorphology that discusses sculpting the Earth’s surface • Water is one of the factors that changes the shape of planet Earth – this is called water erosion • One of the types of soil erosion is water soil erosion - changes, moving of the soil by water – water streams, surface runoff • Moderating climate – In coastal areas less extremes mild winter, hot summers ( but not that hot) • Water is a universal solvent – dissolves in many different chemicals, same is the thing in nature dissolved in rocks • In the long run, Water is doing a great job moving and dissolving the particles • Water is involved in dissolving and diluting particles – • Can be good but can also be something that we might not want • Water also dilutes wastes and pollutants – what happens is move water together with water stream/flow and reach rivers, lakes, ponds, oceans How much fresh water is available? • Not much fresh water is available on Earth • 97.4% of all water is found in oceans and saline lakes • 2.6% in fresh water is available • Of the 2.6% in fresh water most of it is captured as ice caps and glaciers (1.984%) • Water from ice caps and glaciers is not readily available (might be if global warming continues) • Groundwater composes of a significant amount of the fresh water • Groundwater is available for us but we need to pump it out to use it and consume it and also not use it more than it is replenished • There is only 0.014% of readily available fresh water • Of this, 0.007% is found in lakes, 0.005% as soil moisture, some significant amount of water is in atmosphere as water vapor and some as biota (all living organisms) • There are huge amounts of water stored in leaves and vegetation (biota) • And some amount of water in rivers How do we use the world’s fresh water? • There is a comparison between three countries – Canada, U.S. and China (on slide) • There is a significant difference in the use of fresh water between these three countries Life Support EESA10H3 S 01/23/2008 • We are most interested in Canada – 64% of the fresh water is used for power plant cooling, 15% in industry, 12% in public and 9% in agriculture • If you look at the graph of the U.S. much more water is used in the agricultural sector (41%) • United States uses much more water for irrigation in agriculture; China uses even much more (61%) • More specifically how do we use water in households? Too much water is used for conventional use – flushing toilet (30%), showering (35%), laundry (20%), drinking 10% and cleaning (5%) Hydrological poverty • Canada has plentiful water available but what about the people in some areas of the world • People in many developing countries just don’t have enough water for basic things such as drinking or cooking • One out of six people do not have regular access to clean water (safe water to drink) • In many areas such as North Africa and Western Asia people travel far distances to just get a couple of litres of water (they spend half of the day doing it) • They need to do it just to survive (often use polluted water because that is all they can find) • As a result of this diarrheal deaths is very common in developing countries • It is the number one cause of death in children younger than five years old • The biggest risk – 2 million kids die every day (year?) due to diarrheal death • Adults are also under high risk but definitely children are at a huge risk (under 5) • They are dying presently Water and Your health • We are in desperate need for help – drinking water and swimming water Drinking Water • It is our right to know what it is that we drink – what other chemicals (besides molecules of water) that we have in a glass of water that we consume today • Our municipals must provide us with record – they are checking our tap water everyday • Provide us with annual reports on local drinking water quality • It is our right to contact them and get that information • On water bottles it says naturally pure water – water cannot be 100% pure because water naturally has to have some minerals that’s good for our heath • We need calcium, potassium, magnesium, sodium and salts Also calcium carbonate, calcium sulfate • There is no such thing as naturally pure water • Actually there is Distillate water is water without salts – our body needs salts • Our tap water comes from Lake Ontario, far from the shore and deeper on the bottom an example of surface water • Surface water – in most urban areas mostly from rivers, lakes and reservoirs Life Support EESA10H3 S 01/23/2008 • Ground water can also be used for water supply – wells are very common in rural areas • Ground water reservoirs can be very small or extremely huge • There is an ground water reservoir in the U.S.--> thousands of metres deep underground that runs in 6 states • If we withdraw all this water more than can be naturally replenished that water reservoir will shrink and it will not last forever How is drinking water treated? • What do the municipalities do after they take water from rivers, lakes and reservoirs? • They need to clean it, it is not for drinking • First they leave water in tanks to settle down – it is easier later to purify • Then they add coagulants agents (some specially designed chemicals) for this purpose • The chemicals make clumps that settle down the bottom smaller particles – • Coagulate together  heavier then and then settle down in the bottom it is easy to remove them from the water in that way • Water then goes through mechanical filtering and some types of chemical filtering • There are different types of filters to filter bacteria, viruses and protozoa (some microbes that are possibly found in water) • Filters are very good for filtering bacteria but not very good for filtering viruses • There is such a tiny and very small special techniques that need to be used for this types of germs (viruses) • Water then goes for disinfection (addition of chemicals) • Question 2 on your assignment is about addition of chlorine (one type of disinfectant that can be added to water) • More new and advanced techniques are now often implemented and slowly replace convention disinfection • One is granulated activated charcoal – chemical cleaning mostly of organic contaminants • Ion exchange resins – better with heavy metals (mercury, lead) • Reverse osmosis – is a good technique for metals and inorganic contamination • Ground water is cleaner with less concentration of toxic chemicals • This is because it is naturally filtered – soil (consists of different types of chemicals) is working as a natural filter • Water peculating through the soil reacting from different chemicals purify in that way • Thus groundwater often does not need any treatment – it is pure and clean enough already • Groundwater peculating through the soil Reacting with different chemicals and materials and purifying in that way • that’s why ground water is naturally filtered and often doesn’t need any treatment • Also ground water peculating through the soil can dissolve some minerals Life Support EESA10H3 S 01/23/2008 • That is how you can get mineral water or alga mineral water depends on the percentage of each mineral • Some people cannot consume mineral water because of their health (because of the rich minerals) or can be used as a mineral supplement Chlorination of Drinking Water; Its Benefits and Risks (Assignment 1) • The most common disinfectants used for as infection of the water are chlorine, chloramines and hypochlorite – all about chlorination, could be different chemicals not just one • Chlorine reacts with organic matter in water – you always have organic matter because of plants, algae, wood debris, anything you can find in water • Some byproducts (Disinfection by-products) (DBP) are formed in that process and some of them are so complicated – these chemicals have an adverse affect on health • Recent research says that they have adverse affects but the data is not yet completely clear – we do not have results done on humans mostly on research animals • What are the health problems? These
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